Digital Commons Network^™

Cement Stabilization Of Poorly Graded Sand, Lana Grayson Brown Sisung

Theses and Dissertations

Stabilization of poorly graded sand in full-scale applications is challenging. This thesis evaluated cement-stabilized sand and had two objectives: (1) evaluation of stabilized material using the PM device to quantify engineering properties for future comparison to alterative materials and to investigate the effectiveness of the device with sand and (2) investigation of the merits of alternative application of cement to sand to benchmark against other topically applied materials. The PM device was successfully used to recommend 10% cement for field studies with one sand, successfully allowed data collection in laboratory and field applications, and its potential in sand seems promising …

Assessment Of Light Weight Deflectometer For Low Volume Roads Experiencing Rapidly Increased Traffic Levels, Margarita Ordaz

Theses and Dissertations

When evaluating low volume roads (LVRs), structural capacity emphasis is minimal since deterioration typically results from environmental factors. However, in cases where LVR’s experience rapidly increased traffic loading, structural condition becomes important. The research objective was to determine whether the Light Weight Deflectometer (LWD) can be used as a structural evaluation tool for LVRs in the aforementioned conditions. This study explored the capability of LWD equipment in evaluating major factors that influence flexible pavement structural capacity: load induced deterioration, soil moisture, and asphalt temperature. Falling Weight Deflectometer (FWD) and LWD tests were performed to measure pavement structural condition. LWD was …

A New Saturation-Based Framework For Compaction Quality Control, Kevin Clark Miller

Theses and Dissertations

Field compaction control is arguably the most common yet critical quality control procedure in geotechnical engineering. Since the early 1930s, the systematic process for performing quality control of compacted soils has often been performed by measuring the in-place dry unit weight (or density) and as-compacted soil moisture content after placement in a fill. However, the current practice overlooks several facts resulting from comparing soil prepared and compacted in the laboratory to soils placed and compacted in the field. These issues include comparing the compaction energy in the lab versus what is applied in the field, and the behavior of saturated …

Advancements In Geospatial Monitoring Of Structures, Jordan Keith Baldwin

Theses and Dissertations

The need for advancements in geospatial monitoring of structures has evolved naturally as structures have become larger, more complex, and technology has continued to rapidly develop. Greater building heights generally lead to greater challenges for surveyors, limiting the practical use of traditional measurement methods. For this reason, a new complimentary method was developed and implemented to support elevation monitoring activities during construction of the Salesforce Tower in San Francisco, California. While some studies have explored the use of strain gauges to monitor strain development within individual members, the primary contribution of this work is that it presents a practical and …

Aggregate Characteristics For Unpaved Highway Shoulders, Jessica V. Lewis

Theses and Dissertations

This thesis studied unpaved highway shoulders, and in particular shoulders of lower volume asphalt pavements being overlaid. The primary objective was to better understand how different shoulder aggregates perform on lower volume routes with asphalt surfaces and relatively narrow shoulders. A literature review and an evaluation of a full-scale test section containing five aggregate categories in nine test sections over a thirty-four-month period were the primary efforts performed to evaluate unpaved highway shoulders. The study concluded shoulder width measurements were not especially informative, and that California Bearing Ratio measurements were only modestly informative. Crushed concrete outperformed all other aggregates, though …

Wildfire-Altered Geotechnical Soil Properties And Their Impact On Subsequent Landslides, James M. Kellogg

Theses and Dissertations

Wildfires result in altered landscape as well as altered soil properties. Wildfires result in conditions that are more susceptible to geotechnical hazards introducing a potential for cascading events in the surrounding area. Shallow landslides are common geohazards that result in a post-wildfire landscape. With an ever-increasing trend in wildfires, the need to better understand the impact wildfire-altered soil properties play on shallow slope instability is critical to evaluating risks to existing or planned development, mitigation of potentially hazardous conditions, prioritization of post-wildfire planning, and post-wildfire response preparation. The primary objective of this study is to provide a comprehensive overview of …

Lateral Swelling Pressure In Variably Saturated Expansive Clay, Steven Ray Garrett

Theses and Dissertations

Lateral swelling pressure induced in expansive soils upon wetting can adversely impact the performance and integrity of earthen structures and foundations. The yearly cost associated with damage to structures from expansive clays in the United States is estimated to exceed the loss associated with natural disasters such as earthquakes, floods, and hurricanes. The main objective of this dissertation is to provide new insight into the evolution of lateral swelling pressure in variably saturated expensive soils under infiltration via physical testing. In the first part of this study, a new laboratory-scale testing apparatus was built to measure lateral and vertical swelling …

Integrating Steel Slag Aggregates Into Asphalt Paving By Harmonizing Availability, Quality, Economics, And The Environment, Timothy R. Murphy

Theses and Dissertations

This thesis provides guidance on how to balance matters related to the environmental stewardship, market sources, origin and uses, material properties, performance, and economic impact of using slag materials in pavements. The literature on this topic provides numerous references on the use of slag materials for specific applications, and this thesis aims to make use of those references along with other data from the author to describe slag materials from a holistic perspective and provide some suggestions for balancing several factors that impact optimal use of this resource within pavement structures. Discussion is given to the increased importance of recycling …

The Effect Of Four Decades Of Deregulation On Competition And Productivity Of The U.S. Freight Transportation Industry, Seungjae Shin

Theses and Dissertations

This study reviews the competition and productivity of the U.S. freight transportation industry for the past 41 years. This study investigated the trends of HHI market concentration index values and labor productivity values of rail and truck sectors and tried to find any relationships between the two values in the separate periods before and after the abolishment of the ICC. This study also investigated how the existence of a regulatory body impacted productivity of the freight transportation industry by using a Cobb Douglas production function on annual financial statement data in the U.S. stock exchange market. This study found that: …

Physics-Based Modeling Of Post-Wildfire Landslides In Unsaturated Hillslopes, Masood Abdollahi

Theses and Dissertations

Changes in climatic regimes and land use have led to increases in wildfire activities around the world. Wildfires are now happening more frequently, at higher altitudes, and higher severities. Adverse impacts of wildfires can last years after the fire has been contained through post-fire geohazards, such as shallow landslides. Post-wildfire shallow landslides are often mobilized by rainfall and due to fire-induced changes in soil and land cover properties and near-surface processes. This study aims to develop a physics-based framework to evaluate the stability of burned hillslopes against rainfall-triggered shallow landslides. A coupled hydromechanical infiltration model is developed by employing a …

Evaluation For Using Expended Bioelectrochemical Systems As Soil Amendments For Improved Corn Plant Growth And A Drought Resistant Soil., Jackson Lee Sauers

Theses and Dissertations

A long-held practice is to mix agricultural soil with a soil amendment to improve growing conditions in crops. A common soil amendment is biosolids produced from both municipal and dairy wastewater due to the macro- and micronutrients within it. Both the agricultural and wastewater industries are participating in the Circular Economy concept (CEC). Two experiments explored using expended bioelectrochemical systems (BES) that treated either synthetic dairy wastewater (DWW) or synthetic municipal wastewater (SWW) as soil amendments to improve corn plant growth when treated with three different nutrient treatments: 100%- 50%- and 0% Hoagland Nutrient Solutions. Biochar and used terracotta clay …

Inequity Of Access Across America: A Spatial, Temporal, And Modal Disparity Analysis, Sanju Maharjan

Theses and Dissertations

The overarching goal of this dissertation is to examine the spatial, temporal, and modal disparity of access across America. This is achieved by posing three research objectives. The first objective determines the spatial and temporal disparity of transit and automobile access gap, its impact on transit use, and its socioeconomic and built environment correlates. The second objective examines the spatial and temporal disparity of slightly and extremely risky bike infrastructure and measures the social inequity of access to bike infrastructure. The third objective indicates spatial transit access mismatch between high- and low-wage employment across metropolitans. Three findings are discerned. First, …

Resiliency Of Levee-Protected Power Networks To Flooding In A Changing Climate Integrating Environmental Justice, Seyed Saeed Miraee-Ashtiani

Theses and Dissertations

Electric power system (EPS) is an integral part of infrastructure systems. Ensuring its resiliency to extreme weather events and natural hazards is crucial to protect the safety, economy and public health. Recorded and projected data show an increase in the frequency and severity of extreme weather events and natural hazards attributed to a changing climate. It is critical to ensure the integrity of the aging infrastructure systems and to promote environmental justice by shrinking the energy-equity gap to lower power outages in disadvantaged communities.

An important aspect is the resiliency interdependency of EPS to other critical infrastructure systems, an aspect …

Evaluation Of Flood Damage On Cross Laminated Timber Wall Configurations, Mustafa Nezih Kaya

Theses and Dissertations

Greenhouse gas emissions are one of the critical factors that affect climate change, increasing flooding risk and threatening human life. The use of traditional construction materials is responsible for a higher percentage of global greenhouse gas emissions when compared to the use of sustainable materials in the construction industry. The substitution of current building materials with sustainable materials is essential to reduce greenhouse gas emissions and positively influence climate change when the current construction demand in the world is considered. Wood is one of the primary environmentally friendly construction materials in regard to high carbon storage and low carbon emissions. …

Mechanical Property Relationships Of Cement Or Lime Stabilized Soils Throughout A Pavement's Life, Leigh E.W. Ayers

Theses and Dissertations

Soil-cement is an integral part of pavement design, especially in areas that are aggregate deprived, such as Mississippi. Current designs are reliant on the relationship of unconfined compressive strength (UCS) to other mechanical properties. The other properties discussed in this dissertation are Modulus of Elasticity (E), Indirect Tensile Strength (St), and Modulus of Rupture (MOR). This dissertation includes a comprehensive review of past design methods and mechanical property relationships. While some mechanical property relationships were shown to be well understood (i.e. St to UCS), others were not as accurate, especially for the later life mechanical properties (i.e. MOR to UCS …

Impact Of Climate Oscillations/Indices On Hydrological Variables In The Mississippi River Valley Alluvial Aquifer., Meena Raju

Theses and Dissertations

The Mississippi River Valley Alluvial Aquifer (MRVAA) is one of the most productive agricultural regions in the United States. The main objectives of this research are to identify long term trends and change points in hydrological variables (streamflow and rainfall), to assess the relationship between hydrological variables, and to evaluate the influence of global climate indices on hydrological variables. Non-parametric tests, MMK and Pettitt’s tests were used to analyze trend and change points. PCC and Streamflow elasticity analysis were used to analyze the relationship between streamflow and rainfall and the sensitivity of streamflow to rainfall changes. PCC and MLR analysis …

Development And Evaluation Of Seasonal, Continental-Scale Streamflow Forecasts, Elissa Marie Yeates

Theses and Dissertations

Methods of forecasting streamflow using atmospheric ensembles and hydrologic routing have greatly improved over the past decades. These forecasts anticipate the timing and magnitude of streamflow peaks, enabling early warning of floods. Recent advances in atmospheric modeling have enabled production of forecasts months ahead, which are less precise but give a useful sense of trends.

The purpose of this study is to produce and evaluate a seasonal streamflow forecast model using a Muskingum routing hydrologic model coupled with runoff from a land surface model, and atmospheric input from a medium-term atmospheric and precipitation model. To evaluate the skill of the …

Enhancing The Performance Of Dowel Type Fasteners And A Case Study Of Timber Truss Failure, Lon A. Yeary

Theses and Dissertations

This document will outline the findings of three separate and independent studies: Study 1: In or around 1972, an experimental building was constructed. One of the intents of the construction project was to demonstrate advancements in wood building construction design. It was value-engineered throughout. That is, its materials and systems were intended to function at or near design capacity. In 2019, part of the roof of the structure collapsed. This case study investigates two potential factors that led to the failure: stress concentration in excess of the 12 allowable stress for 2 × 4 web members and insufficient plywood sheathing …

Environmental Impact And Life Cycle Assessment Of Biomass Supported Power Systems For Rural Communities, Hariteja Nandimandalam

Theses and Dissertations

Dependence on fossil fuels in the electric sector is one of the major contributors towards Greenhouse gas (GHG) emissions. The increase in renewable contribution has been observed in recent years but there is still potential to utilize wood waste in rural communities for electricity generation promoting energy independence and sustainable development. For this study, a life cycle assessment approach was utilized to estimate the emissions of electricity produced from wood residue in a rural community. Therefore, the process from planting to supply for bioenergy facility to generate electricity are included. The results showed a decrease of 92-96 % in global …

Effects Of The Inclusion Of Rice Hull Derived Bio-Oil On Wood Pellet Production, Tyler E. Lowe

Theses and Dissertations

Wood pellet production has become an advancing industry for the sake of reducing greenhouse emissions into the atmosphere especially, in European Union countries. Researchers and industry executives seek new methods and materials to improve the pelletization process. Rice hulls or husks has the potential to aid in wood pelletization as they possess high calorific values. This study focuses on using rice hull derived bio-oil from pyrolysis, which will also decrease ash content, as an additive to aid in the wood pelletization process. Using two groups of rice hull derived bio-oil as an additive in wood pelletization: Group 1 uses heavy …

Effects Of Bonding Pressure And Lamina Thickness On Mechanical Properties Of Clt Composed Of Southern Yellow Pine, Cody S. Bates

Theses and Dissertations

This study produced cross-laminated timber panels at a range of four lamina thickness (5/8, 1, 1 1/8, and 1 1/4 inch) and three bonding pressures (50, 125, 200 psi), producing a total of 12 panels for mechanical testing. The goal of this study is to observe how the thickness and pressure trends affect the mechanical properties of CLT. Tests include flatwise bending, flatwise shear, internal-bond, and delamination. Results showed that bending MOE decreases as the panel thickness increases while bonding pressure had no significance. Bending MOR was less significant for the thickness and more significant for pressure compared to the …

Field Durability Test Of Clt Wall Envelope Using Physical Barriers Against Termites And Structural Performance Of Nailed Hold-Down Brackets Connected To Fungus-Exposed Clt Walls, Kamal Neupane

Theses and Dissertations

The effectiveness of using commercial polyethylene flashing and stainless-steel mesh in CLT wall systems as the termite barriers were evaluated in a short-term field test. American Wood Protection Association (AWPA) E21's visual ratings ranged from 10 to 9 in the specimens showing little damage when no physical barriers were used. Termites were able to crawl beyond the physical barriers in few specimens showing the necessity of further research on height and installation method of physical barriers. On the second part, the effect of decay caused due to Postia placenta, a brown-rot fungus, on the structural performance of hold-down brackets connected …

Mixing Temperature, Binder Content, And Dust Content Effects On Stone Matrix Asphalt, Abhinash Subedi

Theses and Dissertations

This study focuses on the effects of mixing temperature, binder content, and dust content on the performance of Stone Matrix Asphalt (SMA). Mixes produced at different mixing temperatures and with or without added polymer modified binder (P_b) and/or bag house dust (BHD) were evaluated. Two different types of specimens: laboratory mixed laboratory compacted, and plant mixed laboratory compacted were evaluated by Cantabro Mass Loss (CML) testing in an unaged condition or after a laboratory conditioning protocol (CP) was applied. Additional P_b and BHD were added to plant produced mixes in the laboratory before mixing. Results showed that …